https://gitlab.synchro.net/main/sbbs/-/commit/9b3be7dc63b3bb6a4b8a3e4e
Modified Files:
	src/sbbs3/answer.cpp date_str.c date_str.h ftpsrvr.c js_global.c logout.cpp main.cpp nopen.c nopen.h sbbsecho.c
Log Message:
Only allow one FTP session per QWKnet user account

Vertrauen's FTP server gets abused by QWKnet logins sometimes and handling
the race conditions around QWK packet creation attempts is silly - there's
no legit reason why a QWKnet account needs to be logged-in multiple times
concurrently to the hub's FTP server, so reject the subsequent logins even
when they're on different hosts (as is the case with Vertrauen).

As part of this change:
- fmutex() now takes an new time_t* argument to (optionally) store the
  time of the mutex file for helping logging (locked since when?).
- time_as_hhmm() created to format a string as either HH:MM or HH:MM[a|p]
  (depending on system configuration for 12 or 24 hour time formatting).
- renamed the old hhmmtostr ()to tm_as_hhmm() (since it takes a struct tm arg)
  and have it return a non-padded string (useful in more situations without
  requiring truncation) when the sysop prefers 24-hour time.
--- SBBSecho 3.22-Linux